Ashby 2012.

Study characteristics
Methods	2‐arm RCT Conducted in home and hospital settings in 1 geographical location in the UK Duration of follow‐up was a maximum of 24 weeks
Participants	44 participants: all included in the analysis Inclusion criteria listed: pressure ulcer graded III or IV according to the European Pressure Ulcer Advisory Panel Grading System; must receive primary care via Leeds Primary Care Trust; ulcer should contain at least 80% viable tissue or have a very thin layer of slough (nonviable tissue) requiring no further debridement prior to use of NPWT Exclusion criteria listed: the presence of unclear undermining in the pressure ulcer cavity precluding the use of NPWT; pressure ulcer with necrotic tissue, eschar, or necrotic bone present; the patient has limited life expectancy; pressure ulcer located where, in the opinion of the treating clinician, a vacuum seal could not be obtained; pressure ulcer too close to exposed blood vessels or organs, or both, anastomotic sites or nerves, or both; patient unable to give valid informed consent because of incapacity; the patient was unable to consent as trial materials were not available in a suitable language; the patient did not wish to consent to participation within a trial; a clinical judgment was made that the patient was not receiving adequate nutrition to allow treatment with NPWT; other reasons, in the clinical judgment of the treating clinician or nurse, which excluded the patient from the trial
Interventions	Group A: the wound was closed using a Wound Care Kit that includes foam dressing (V.A.C. Granu Foam Silver), film drape, TRAC pad with tubing and a drainage canister. Steril foam material was placed inside the wound and was attached to the canister through tubing. The canister was attached to the Vacuum‐Assisted Closure device (V.A.C.® Therapy System Patient Support – KCI), which is a portable device that applies intermittent or continuous negative pressure. The device was operated at 125 mmHg pressure for 5 min with and 2 min without active vacuum. Wound dressings were changed every 48 h. The wound area was measured after all three rounds of treatment. Offloading of the sore was performed by position change, airflow mattress usage and it was taken into consideration not to raise the head of the bed, more than 30◦ Group B: The wound was initially evaluated for any necrotic findings and debrided if needed, and then washed with an antiseptic solution. A culture specimen was obtained from the wound. 3DWM was used to measure the pressure sores by taking pictures. The length and width of wounds were measured with disposable paper rulers. Wound depth was determined in centimetres with a sterile cotton‐tip applicator by measuring against a ruler. Wounds were finally covered with gauze dressing soaked with saline. Wounds were treated three times a day, and measurements were repeated every 48 h.   Co‐interventions: none described
Outcomes	Primary outcomes: complete wound healing (% ulcers healed) Secondary outcomes: adverse events
Notes	Pilot study Only one ulcer per participant was followed Duration of follow‐up differed between groups: mean duration was 3.8 months for Group A and 5.0 months for Group B Funding: Supported by the Medical Research Council
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomisation was conducted using pre‐generated random permuted blocks (block sizes of four and six). A data manager at the York Trials Unit, who was completely independent of the research team, created the randomisation programme" Comment: adequate
Allocation concealment (selection bias)	Low risk	Quote: "the research nurse telephoned a secure and remote randomisation service, located at the York Trials Unit (University of York, UK)." Comment: central allocation was used to conceal allocation
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Wound healing Quote: "We piloted a blinded outcome assessment process using digital photographs of the wound taken using the mobile camera phone" Comment: blinding of key study personnel used and unlikely that the blinding could have been broken Adverse events Comment: not blinded Resource use Comment: not blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: flow chart shows that all participant data were included in analysis
Selective reporting (reporting bias)	Low risk	Comment: outcomes identified in the methods section were reported in the results (and were outcomes that would be expected to be included in such a study). Protocol not seen. Only 1 participant's pressure ulcer healed so not possible to calculate mean 'time to healing'
Other bias	Unclear risk	No unit of analyses issues Quote: "Whilst the research nurse was primarily responsible for data collection, this responsibility was also delegated to nurses treating patients in acute and community settings." Comment: there may have been inconsistency in reporting between community nurses